NIST SP 800-171 Rev. 3 3.4.4 — Impact Analyses

What this control requires

This control requires conducting impact analyses prior to implementing system changes to determine potential security impacts. It also mandates verifying that security requirements are still met after the changes are implemented. The analysis includes reviewing security plans, design documentation, and operational procedures to evaluate risks and necessary security adjustments. This control supports the Risk Assessment System capability within the Configuration Management (3.4) family.

In plain English

This control requires conducting impact analyses prior to implementing system changes to determine potential security impacts. In practice, this means you can prove you configuration management-level controls on a defined cadence.

Why it matters

DoD contractors and their subcontractors must implement all 100 SP 800-171 requirements to keep CUI handling contracts. Gaps are scored against the SPRS scoring methodology; below a 110-point starting score, each unmet requirement deducts points and a below-threshold score can disqualify a bid.

This control is rated high. Auditors expect a named owner, a remediation SLA, and a tooling artefact that evidences continuous operation.

What an auditor looks for

A C3PAO conducting a CMMC Level 2 assessment uses NIST SP 800-171A objectives. They expect a System Security Plan (SSP), Plan of Action & Milestones (POA&M) for any gaps, and objective evidence (configurations, ticket records, training records) for every requirement.

Within Configuration Management, the assessor will trace your implementation back to the catalogue reference (Requirement 3.4.4) and look for objective evidence on the latest two assessment cycles.

How to implement

Policy Management

Docs. Keep each policy in version-controlled Markdown alongside the code that implements it; ship a signed PDF snapshot at each annual review and link the SHA into the SoA.

Operational checklist

• Configuration. Document the trigger, the owner and the cadence.
• Impact. Document the trigger, the owner and the cadence.
• System. Document the trigger, the owner and the cadence.
• Risk. Document the trigger, the owner and the cadence.
• Security. Document the trigger, the owner and the cadence.
• Scope: management, configuration, analyses, analysis, security, assessment, procedures, design.

Evidence to collect

• Policy Document. A signed and version-controlled policy / standard / procedure document.

Signed policy or standard documents the safeguard. Focus: Impact Analyses.

Common pitfalls

• Policies that no engineer has read; the version in Confluence drifts from the version that's actually being enforced.

How it maps to other frameworks

Computed from shared tags, control component and key-operation subjects — handy when you are reconciling controls across an audit.

• NIST SP 800-53 Rev. 5 CM-4 — Impact Analyses
• HIPAA (45 CFR Part 164) 164.308(a)(5)(ii)(B) — Security Awareness, Training, and Tools - Protection from Malicious Software
• ISO/IEC 27001:2022 A.5.1 — Policies for information security
• BSI C5:2020 SP-01 — Documentation, communication and provision of policies and instructions
• SOC 2 (2017 TSC) CC3.3 — Fraud Risk Assessment

Related controls in NIST SP 800-171 Rev. 3

• Requirement 3.4.1 — Baseline Configuration
• Requirement 3.4.8 — Authorized Software - Allow by Exception
• Requirement 3.12.1 — Security Assessment
• Requirement 3.4.11 — Information Location
• Requirement 3.11.4 — Risk Response
• Requirement 3.12.3 — Continuous Monitoring

References

• NIST Computer Security Resource Center — NIST SP 800-171 Rev. 3
• Catalogue identifier: Requirement 3.4.4

Topics: governance riskpolicy management